Sitecore How-To: Create Dynamic Source Field Query for Treelists and Multilists in Sitecore

• Overview
• How-To
• Step-by-step guide

Overview

This is an article in a series of Sitecore how-to articles. These articles are meant to be quick guides to accomplish various tasks within Sitecore. The how-to articles have proven to be very helpful internally at One North Interactive https://www.onenorth.com. These articles assume working Sitecore knowledge. I just wanted to share the articles with the community. Hopefully you find them helpful.

How-To

Treelist and Multilist fields in Sitecore provide a way of specifying what is displayed and what is selectable in a selection pane of the field in Source field. Out-of-the-box you can use sitecore queries to populate these fields. For example, if you need a field that allows you to select Highlights your Source property may look something like:

DataSource=/sitecore/content/sites/main/home/highlights/

You could further constrain the elements in the selection pane by using the following parameters:

• IncludeTemplatesForSelection: Users can only select items based on this comma-separated list of data template names.
• ExcludeTemplatesForSelection: Users cannot select items based on this comma-separated list of data template names.
• IncludeTemplatesForDisplay:Users can view items based on this comma-separated list of data template names and IDs.
• ExcludeTemplatesForDisplay: Users cannot navigate items based on this comma-separated list of data template names.
• IncludeItemsForDisplays: Users can navigate items based on this comma-separated list of item names and IDs.
• ExcludeItemsForDisplay: Users cannot navigate items based on this comma-separated list of item names and IDs.
• AllowMultipleSelection: If yes, users can select the same item more than once.

More information about these parameters can be found in this blog post or in Data Definition Cookbook (page 12-13).

Additionally, you can create a fully dynamic list of available items in Source field where you can implement custom client-specific business logic for populating selectable values.

Step-by-step guide

1. Include Sitecore.Buckets.dll as a reference to in your project

2. Create a new class that implements Sitecore.Buckets.FieldTypes.IDataSource interface and returns a custom array of Items. You could use Lucene here but will need to convert search results back into Sitecore items

    using Sitecore.Buckets.FieldTypes;
    using Sitecore.Data.Items;
    using System;
    using System.Collections.Generic;
    using System.Linq;
       
    namespace Website.Logic.CustomDataSources
    {
        public class RelatedInsightsDataSource : IDataSource
        {
            public Item[] ListQuery(Item item)
            {
                List<Item> dataSource = new List<Item>();
                //add your custom logic here that gets a list of source items for your multilist
       
                return dataSource.ToArray();
       
            }
        }
    }
   

3. Update a source field for the field you are updating with your own class: code:Website.Logic.CustomDataSources.RelatedInsightsDataSource, Website